basicscrollpaneui.java

来自「JAVA的一些源码 JAVA2 STANDARD EDITION DEVELO」· Java 代码 · 共 948 行 · 第 1/3 页

            else if (key == SCROLL_DOWN) {
                scroll(scrollPane, SwingConstants.VERTICAL, 1, true);
            }
            else if (key == SCROLL_HOME) {
                scrollHome(scrollPane);
            }
            else if (key == SCROLL_END) {
                scrollEnd(scrollPane);
            }
            else if (key == UNIT_SCROLL_UP) {
                scroll(scrollPane, SwingConstants.VERTICAL, -1, false);
            }
            else if (key == UNIT_SCROLL_DOWN) {
                scroll(scrollPane, SwingConstants.VERTICAL, 1, false);
            }
            else if (key == SCROLL_LEFT) {
                scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? -1 : 1,
                       true);
            }
            else if (key == SCROLL_RIGHT) {
                scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? 1 : -1,
                       true);
            }
            else if (key == UNIT_SCROLL_LEFT) {
                scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? -1 : 1,
                       false);
            }
            else if (key == UNIT_SCROLL_RIGHT) {
                scroll(scrollPane, SwingConstants.HORIZONTAL, ltr ? 1 : -1,
                       false);
            }
        }

        private void scrollEnd(JScrollPane scrollpane) {
	    JViewport vp = scrollpane.getViewport();
	    Component view;
	    if (vp != null && (view = vp.getView()) != null) {
		Rectangle visRect = vp.getViewRect();
		Rectangle bounds = view.getBounds();
		if (scrollpane.getComponentOrientation().isLeftToRight()) {
		    vp.setViewPosition(new Point(bounds.width - visRect.width,
					     bounds.height - visRect.height));
		} else {
		    vp.setViewPosition(new Point(0, 
					     bounds.height - visRect.height));
		}
	    }
        }

        private void scrollHome(JScrollPane scrollpane) {
	    JViewport vp = scrollpane.getViewport();
	    Component view;
	    if (vp != null && (view = vp.getView()) != null) {
		if (scrollpane.getComponentOrientation().isLeftToRight()) {
		    vp.setViewPosition(new Point(0, 0));
		} else {
		    Rectangle visRect = vp.getViewRect();
		    Rectangle bounds = view.getBounds();
		    vp.setViewPosition(new Point(bounds.width - visRect.width, 0));
		}
            }
        }

	private void scroll(JScrollPane scrollpane, int orientation,
                            int direction, boolean block) {
	    JViewport vp = scrollpane.getViewport();
	    Component view;
	    if (vp != null && (view = vp.getView()) != null) {
		Rectangle visRect = vp.getViewRect();
		Dimension vSize = view.getSize();
		int amount;

		if (view instanceof Scrollable) {
		    if (block) {
			amount = ((Scrollable)view).getScrollableBlockIncrement
			         (visRect, orientation, direction);
		    }
		    else {
			amount = ((Scrollable)view).getScrollableUnitIncrement
			         (visRect, orientation, direction);
		    }
		}
		else {
		    if (block) {
			if (orientation == SwingConstants.VERTICAL) {
			    amount = visRect.height;
			}
			else {
			    amount = visRect.width;
			}
		    }
		    else {
			amount = 10;
		    }
		}
		if (orientation == SwingConstants.VERTICAL) {
		    visRect.y += (amount * direction);
		    if ((visRect.y + visRect.height) > vSize.height) {
			visRect.y = Math.max(0, vSize.height - visRect.height);
		    }
		    else if (visRect.y < 0) {
			visRect.y = 0;
		    }
		}
		else {
		    if (scrollpane.getComponentOrientation().isLeftToRight()) {
			visRect.x += (amount * direction);
			if ((visRect.x + visRect.width) > vSize.width) {
			    visRect.x = Math.max(0, vSize.width - visRect.width);
			} else if (visRect.x < 0) {
			    visRect.x = 0;
			}
		    } else {
			visRect.x -= (amount * direction);
                        if (visRect.width > vSize.width) {
                            visRect.x = vSize.width - visRect.width;
                        } else {
                            visRect.x = Math.max(0, Math.min(vSize.width - visRect.width, visRect.x));
			}
		    }
		}
		vp.setViewPosition(visRect.getLocation());
	    }
	}
    }


    class Handler implements ChangeListener, PropertyChangeListener, MouseWheelListener {
        //
        // MouseWheelListener
        //
        public void mouseWheelMoved(MouseWheelEvent e) {
            if (scrollpane.isWheelScrollingEnabled() &&
                e.getScrollAmount() != 0) {
                JScrollBar toScroll = scrollpane.getVerticalScrollBar();
                int direction = 0;
                // find which scrollbar to scroll, or return if none
                if (toScroll == null || !toScroll.isVisible()) { 
                    toScroll = scrollpane.getHorizontalScrollBar();
                    if (toScroll == null || !toScroll.isVisible()) { 
                        return;
                    }
                }
                direction = e.getWheelRotation() < 0 ? -1 : 1;
                if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {
                    BasicScrollBarUI.scrollByUnits(toScroll, direction,
                                                         e.getScrollAmount());
                }
                else if (e.getScrollType() ==
                         MouseWheelEvent.WHEEL_BLOCK_SCROLL) {
                    BasicScrollBarUI.scrollByBlock(toScroll, direction);
                }
            }
        }


        //
        // ChangeListener: This is added to the vieport, and hsb/vsb models.
        //
	public void stateChanged(ChangeEvent e) {
            JViewport viewport = scrollpane.getViewport();

            if (viewport != null) {
                if (e.getSource() == viewport) {
                    viewportStateChanged(e);
                }
                else {
                    JScrollBar hsb = scrollpane.getHorizontalScrollBar();
                    if (hsb != null && e.getSource() == hsb.getModel()) {
                        hsbStateChanged(viewport, e);
                    }
                    else {
                        JScrollBar vsb = scrollpane.getVerticalScrollBar();
                        if (vsb != null && e.getSource() == vsb.getModel()) {
                            vsbStateChanged(viewport, e);
                        }
                    }
                }
            }
        }

        private void vsbStateChanged(JViewport viewport, ChangeEvent e) {
            BoundedRangeModel model = (BoundedRangeModel)(e.getSource());
            Point p = viewport.getViewPosition();
            p.y = model.getValue();
            viewport.setViewPosition(p);
        }

        private void hsbStateChanged(JViewport viewport, ChangeEvent e) {
            BoundedRangeModel model = (BoundedRangeModel)(e.getSource());
            Point p = viewport.getViewPosition();
            int value = model.getValue();
            if (scrollpane.getComponentOrientation().isLeftToRight()) {
                p.x = value;
            } else {
                int max = viewport.getViewSize().width;
                int extent = viewport.getExtentSize().width;
                int oldX = p.x;

                /* Set new X coordinate based on "value".
                 */
                p.x = max - extent - value;

                /* If setValue() was called before "extent" was fixed,
                 * turn setValueCalled flag on.
                 */
                if ((extent == 0) && (value != 0) && (oldX == max)) {
                    setValueCalled = true;
                } else {
                    /* When a pane without a horizontal scroll bar was
                     * reduced and the bar appeared, the viewport should
                     * show the right side of the view.
                     */
                    if ((extent != 0) && (oldX < 0) && (p.x == 0)) {
                        p.x += value;
                    }
                }
            }
            viewport.setViewPosition(p);
        }

        private void viewportStateChanged(ChangeEvent e) {
            syncScrollPaneWithViewport();
	}


        //
        // PropertyChangeListener: This is installed on both the JScrollPane
        // and the horizontal/vertical scrollbars.
        //

        // Listens for changes in the model property and reinstalls the
        // horizontal/vertical PropertyChangeListeners.
        public void propertyChange(PropertyChangeEvent e) {
            if (e.getSource() == scrollpane) {
                scrollPanePropertyChange(e);
            }
            else {
                sbPropertyChange(e);
            }
        }

        private void scrollPanePropertyChange(PropertyChangeEvent e) {
            String propertyName = e.getPropertyName();

	    if (propertyName == "verticalScrollBarDisplayPolicy") {
		updateScrollBarDisplayPolicy(e);
	    }
	    else if (propertyName == "horizontalScrollBarDisplayPolicy") {
		updateScrollBarDisplayPolicy(e);
	    }
	    else if (propertyName == "viewport") {
		updateViewport(e);
	    }
	    else if (propertyName == "rowHeader") {
		updateRowHeader(e);
	    }
	    else if (propertyName == "columnHeader") {
		updateColumnHeader(e);
	    }
	    else if (propertyName == "verticalScrollBar") {
		updateVerticalScrollBar(e);
	    }
	    else if (propertyName == "horizontalScrollBar") {
		updateHorizontalScrollBar(e);
	    }
	    else if (propertyName == "componentOrientation") {
		scrollpane.revalidate();
		scrollpane.repaint();
	    }
        }

        // PropertyChangeListener for the horizontal and vertical scrollbars.
        private void sbPropertyChange(PropertyChangeEvent e) {
            String propertyName = e.getPropertyName();
            Object source = e.getSource();

            if ("model" == propertyName) {
                JScrollBar sb = scrollpane.getVerticalScrollBar();
                BoundedRangeModel oldModel = (BoundedRangeModel)e.
                                     getOldValue();
                ChangeListener cl = null;

                if (source == sb) {
                    cl = vsbChangeListener;
                }
                else if (source == scrollpane.getHorizontalScrollBar()) {
                    sb = scrollpane.getHorizontalScrollBar();
                    cl = hsbChangeListener;
                }
                if (cl != null) {
                    if (oldModel != null) {
                        oldModel.removeChangeListener(cl);
                    }
                    if (sb.getModel() != null) {
                        sb.getModel().addChangeListener(cl);
                    }
                }
            }
            else if ("componentOrientation" == propertyName) {
                if (source == scrollpane.getHorizontalScrollBar()) {
		    JScrollBar hsb = scrollpane.getHorizontalScrollBar();
 		    JViewport viewport = scrollpane.getViewport();
                    Point p = viewport.getViewPosition();
                    if (scrollpane.getComponentOrientation().isLeftToRight()) {
                        p.x = hsb.getValue();
                    } else {
                        p.x = viewport.getViewSize().width - viewport.getExtentSize().width - hsb.getValue();
                    }
                    viewport.setViewPosition(p);
                }
            }
        }
    }
}